A turbo blower or a turbo compressor is a centrifugal pump configured to rotate an impeller at a high speed to intake external air or external gas, in order to send the air or gas to the outside after compressing the air or gas, and is widely used for powder transportation or aeration in a sewage disposal plant.
A conventional turbo blower includes a product configured to rotate the impeller by using a rotational force of an electric motor. For such a turbo blower, an inverter configured to generate a high speed current waveform for controlling a speed of a motor and supply the high speed current waveform to the motor is essentially needed.
However, most inverters include a heat radiating element, such as an insulated gate bipolar transistor (IGBT), and the IGBT, which is an electrical device for generating a high speed current waveform, generates a large amount of heat due to electrical switching, and thus, for a continual operation of the motor, a continual cooling operation of the IGBT is needed. Moreover, the amount of heat generated by the IGBT increases in proportion to a switching frequency.
The conventional turbo blower uses a method (a compulsory air-cooled method) of cooling the inverter by using air by rotating a cooling fan or a method (a water-cooled method) of cooling the inverter by using a refrigerant, such as cooling water, in order to cool the inverter.
In the case of the compulsory air-cooled method, a small cooling fan, in which a direct current (DC) motor having relatively less power consumption is mounted, is used in general. However, this small cooling fan has a relatively low capability of supplying cooling air and has a very short life span.
In the case of the water-cooled method, a cooling efficiency is relatively high, but a complex structure such as a water tank or a radiator has to be used, and the danger of leakage of the cooling water is high.
In addition, the conventional turbo blower has a structure whereby the heat generated from the inverter and the heat generated from the motor may be mixed, and thus, a gas heated by the motor may flow into the impeller.